Cellular confinement structures serve to increase the load bearing capacity, stability and erosion resistance of materials which are placed within the cells of the system. A commercially available system is Geowebe plastic web soil confinement structure, sold by Presto Products, Incorporated, P.O. Box 2399, Appleton, Wis. 54913. Geoweb.RTM. cells are made from high density polyethylene strips which are joined by ultrasonic seams on their faces in a side by side relationship at alternating spacings so that when the strips are stretched out in a direction perpendicular to the faces of the strips, the resulting web section is honeycomb-like in appearance, with sinusoidal or undulant shaped cells. Geoweb.RTM. sections are light-weight and are shipped in their collapsed form for ease in handling and installation.
The web materials have been used extensively to provide road bases, subgrades or pavement systems. Structural foundations have been reinforced or stiffened with the web materials. Additionally, Geoweb.RTM. cells have been used to provide earth and liquid retention structures by stacking one web layer upon another, such as a stepped back design for hill slope retention. The Geoweb.RTM. cells also protect earth slopes, channels, revetments and hydraulic structures from surface erosion. Grass and other earth slope cover materials have been protected and stabilized through the use of the web cells.
Geoweb.RTM. cells can be infilled with various earth materials such as sand, rounded rock, granular soils and aggregates, topsoil, vegetative materials and the like. Concrete and soil-cement or asphaltic-cement can also be used to infill the cells.
Materials, such as stone, are ideal for construction because of their very high internal friction angles. The drawback with these construction materials are the lack of cohesion factors which result in the need to confine the materials. A cellular confinement structure, such as Geoweb.RTM., provides a cohesive factor by confining the materials, but does not provide the same friction angle because the confinement structure introduces a slip plane in which the stone has a lower interface friction angle. Therefore, the stone does not perform at its internal friction angle. If the interface friction angle can be increased, the load bearing capacity will also be increased.
An improvement in the load bearing capacity can result in stronger structural designs with higher factors of safety and more cost effective designs for civil engineering applications such as in road base or retaining wall designs. Load bearing capacity has been increased in a texturized cell material structure using a sand infill by the improvement of this interface friction angle. U.S. Pat. No. 4,965,097. However, the texturized cell wall does not perform as well in increasing the interface friction angle on larger construction materials, such as stone.
There is a need in the industry for a cell confinement structure that significantly improves load bearing capacity on construction materials, such as stone, by increasing the interface friction angle, while still maintaining the strength of the cellular confinement structure.